how to configure a FreeBSD firewall to pass IPSec?

[Guy Middleton]

Thanks to everybody for the suggestions, I'll try them this weekend.

The discussion brings up a question:

Until now (and as recommended in the Handbook), I have been using ifpw
and natd.  Everybody here who has IPSec client passthrough working seems
to use ifw/ipnat.  Is ipf/ipnat more flexible? And why is there more than
one firewalling scheme in FreeBSD?